Liquid Level Sensing using Lamb waves

The present study examines the possibility of using an ultrasonic guided wave technique for liquid level sensing. The setup consists of an Aluminium thin beam which is partly immersed in a liquid whose level is to be determined. When a wave guide is immersed in the liquid, guided wave in the waveguide is attenuated due to the leakage of its energy into the surrounding water. The amount of leakage is related to the characteristics of the waveguide and the surrounding liquid liquid. With these predictions, it is possible to relate the measured characteristics to the liquid level. Previous research shows that the various modes of Lamb waves are influenced by the surrounding liquid. Therefore, the change in the characteristic of Lamb waves can be used as a function of liquid level. This effect has also been investigated using Finite Element Analysis.